Ext.ux.TreeCheckNodeUI = Ext.extend(Ext.tree.TreeNodeUI, {
	constructor : function() {
		this.checkModel = 'multiple';// 'multiple':多选; 'single':单选;'cascade':级联多选												
		this.onlyLeafCheckable = false;// only leaf can checked
		Ext.ux.TreeCheckNodeUI.superclass.constructor.apply(this, arguments);
	},
	onDblClick : function(e) {// override private
		e.preventDefault();
		if (this.disabled) {
			return;
		}
		this.fireEvent("dblclick", this.node, e);
	},
	renderElements : function(n, a, targetNode, bulkRender) {
		var tree = n.getOwnerTree();
		this.checkModel = tree.checkModel || this.checkModel;
		this.onlyLeafCheckable = tree.onlyLeafCheckable || false;

		// add some indent caching, this helps performance when
		// rendering a large tree
		this.indentMarkup = n.parentNode ? n.parentNode.ui.getChildIndent() : '';

		var cb = (!this.onlyLeafCheckable || a.leaf);
		var href = a.href ? a.href : Ext.isGecko ? "" : "#";
		var buf = ['<li class="x-tree-node"><div ext:tree-node-id="', n.id, '" class="x-tree-node-el x-tree-node-leaf x-unselectable ', a.cls, '" unselectable="on">', '<span class="x-tree-node-indent">', this.indentMarkup, "</span>", '<img src="', this.emptyIcon, '" class="x-tree-ec-icon x-tree-elbow" />', '<img src="', a.icon || this.emptyIcon, '" class="x-tree-node-icon', (a.icon ? " x-tree-node-inline-icon" : ""), (a.iconCls ? " " + a.iconCls : ""), '" unselectable="on" />', cb ? ('<input class="x-tree-node-cb" type="checkbox" ' + (a.checked ? 'checked="checked" />' : '/>')) : '', '<a hidefocus="on" class="x-tree-node-anchor" href="', href, '" tabIndex="1" ', a.hrefTarget ? ' target="' + a.hrefTarget + '"' : "", '><span unselectable="on">', n.text, "</span></a></div>", '<ul class="x-tree-node-ct" style="display:none;"></ul>', "</li>"].join('');

		var nel;
		if (bulkRender !== true && n.nextSibling && (nel = n.nextSibling.ui.getEl())) {
			this.wrap = Ext.DomHelper.insertHtml("beforeBegin", nel, buf);
		} else {
			this.wrap = Ext.DomHelper.insertHtml("beforeEnd", targetNode, buf);
		}

		this.elNode = this.wrap.childNodes[0];
		this.ctNode = this.wrap.childNodes[1];
		var cs = this.elNode.childNodes;
		this.indentNode = cs[0];
		this.ecNode = cs[1];
		this.iconNode = cs[2];
		var index = 3;
		if (cb) {
			this.checkbox = cs[3];
			Ext.fly(this.checkbox).on('click', this.check.createDelegate(this, [null]));
			index++;
		}
		this.anchor = cs[index];
		this.textNode = cs[index].firstChild;
	},

	// private
	check : function(checked) {
		var n = this.node;
		var tree = n.getOwnerTree();
		this.checkModel = tree.checkModel || this.checkModel;

		if (checked === null) {
			checked = this.checkbox.checked;
		} else {
			this.checkbox.checked = checked;
		}

		n.attributes.checked = checked;
		tree.fireEvent('check', n, checked);

		if (!this.onlyLeafCheckable && this.checkModel == 'cascade') {
			var parentNode = n.parentNode;
			if (parentNode !== null) {
				this.parentCheck(parentNode, checked);
			}
			if (!n.expanded && !n.childrenRendered) {
				n.expand(false, false, this.childCheck);
			} else {
				this.childCheck(n);
			}
		} else if (this.checkModel == 'single') {
			var checkedNodes = tree.getChecked();
			for (var i = 0; i < checkedNodes.length; i++) {
				var node = checkedNodes[i];
				if (node.id != n.id) {
					node.getUI().checkbox.checked = false;
					node.attributes.checked = false;
					tree.fireEvent('check', node, false);
				}
			}
		}

	},

	// private
	childCheck : function(node) {
		var a = node.attributes;
		if (!a.leaf) {
			var cs = node.childNodes;
			var csui;
			for (var i = 0; i < cs.length; i++) {
				csui = cs[i].getUI();
				if (csui.checkbox.checked ^ a.checked)
					csui.check(a.checked);
			}
		}
	},

	// private
	parentCheck : function(node, checked) {
		var checkbox = node.getUI().checkbox;
		if (typeof checkbox == 'undefined')
			return;
		if (!(checked ^ checkbox.checked))
			return;
		if (!checked && this.childHasChecked(node))
			return;
		checkbox.checked = checked;
		node.attributes.checked = checked;
		node.getOwnerTree().fireEvent('check', node, checked);

		var parentNode = node.parentNode;
		if (parentNode !== null) {
			this.parentCheck(parentNode, checked);
		}
	},

	// private
	childHasChecked : function(node) {
		var childNodes = node.childNodes;
		if (childNodes || childNodes.length > 0) {
			for (var i = 0; i < childNodes.length; i++) {
				if (childNodes[i].getUI().checkbox.checked)
					return true;
			}
		}
		return false;
	},

	toggleCheck : function(value) {
		var cb = this.checkbox;
		if (cb) {
			var checked = (value === undefined ? !cb.checked : value);
			this.check(checked);
		}
	}
});